Poppy and James appear in the first Night World book Secret Vampire. They have been best friends for years, ever since Poppy helped out James
when he was getting picked on in elementary school. When Poppy was dying
from cancer James revealed a deeply held secret and turned her into a vampire.

James sums up his and Poppy’s relationship
best with these words “You don’t love somebody because of their looks or their
clothes or their car. You love them because they sing a song that nobody
but you can understand.”

Poppy and James seem to know one another inside out. This is especially important
to James since not that many people seem to know the real him. Like
Poppy says, James has a reputation for being “tough and dangerous.” She’s
one of the only people who knows that he’s really a caring, sensitive guy.
It’s Poppy who helps teach James not to hold himself in such tight restriction.
They share many of the same interests, including trance music.
James can make Poppy laugh and cheer her when she’s upset. He comforts
her when she needs it. As Poppy tells him "I've always been safe with you."
The truth is you’d be hard pressed to find a reason for them not to be
together. This relationship is one of sharing and comfort and understanding.
It doesn’t take much analysis to see that these two belong together.